The present invention relates to a housing for an electronic apparatus accomodating an electronic unit inclnding heat-generating parts, and more particularly, to a housing for an electronic apparatus having an improved cooling air intake port thereof.
A typical apparatus using such a housing is an electronic computer comprising a plurality of high heat-generating elements.
A conventional cooling construction for a frame of an electronic apparatus is disclosed in JP-A-58-114900.
A frame 1 of an electronic apparatus corresponding to a housing to which the present invention is directed, as shown in FIG. 1, has a front door 2 thereof curved in arcuately protruded form. About one half part of the door is provided with an air inlet port 3 to facilitate the intake of the cool air, so that the air flow between the room and the frame of the electronic apparatus is improved thereby improving the heat rediation of the circuit blocks.
In this conventional system, the flow of the cooling air in the room is considered to be limited to a single direction indicated by arrows as shown in FIG. 2.
Generally, an electronic computer has an air inlet port in the front part of the door, and the air sucked in is divided into right and left paths in the housing and discharged from an exhaust port formed in the ceiling. The aforementioned conventional housing, which is used with a small apparatus and performs its function sufficiently with slits formed in the door, is not employed in the field of computer.
The CLASSIC series of computer of MODCOMP and Model MV/10000 of ECLIPSE, and HIDIC80/E computer of Hitachi, for example, has a flat surface of air inlet port.
The prior-art housing construction described above pays no special attention to the reduction in the velocity of intake air and the noises produced by the blower fan. These problems are posed against the strong cooling system of a large-sized computer which tends to an increasingly great amount of heat.
Specifically, the reduction in the size of apparatuses is a very important factor for marketing, and therefore it is necessary to reduce the size of the air inlet space as far as possible.
In order to maintain the reliability of the apparatus, on the other hand, the control of a temperature increase below a certain level is required. For the purpose of covering the high heat generation of an apparatus, therefore, a blower fan with a great air-blowing capacity is required. The noise of the blower fan reaches as high a level as 80 dB. Further, the cooling air driven by this blower fan reaches a velocity of 8 to 10 m/sec on the surface of a heat-generating part and 3 to 5 m/sec even on the air inlet port thereby creating two problems problems.
Firstly, a high air velocity on the inlet port causes paper or the like to attach to the inlet port and reduces the air intake area of the inlet port, thus decreasing the cooling air capacity. Secondly, in spite of the fact that noises of a blower fam may be reduced to 60 dB by arranging a noise-absorbing material appropriately, direct noises remain unabsorbed. The noise-absorbing material thus has its own limit. Because of the short distance between the noise source and the inlet port, on the other hand, the energy attenuation is so small as to make it impossible to reduce the noise level to the order of 55 dB as required for a residential space. Further improvements are thus required.